The present invention relates to diagnostic ultrasound systems. In particular, the present invention relates to methods and apparatus for acquiring and processing ultrasound data to reduce blurring of ultrasound images.
At least some known ultrasound systems are capable of spatially compounding a plurality of ultrasound images of a given target into a compound image. The term “compounding” as used throughout means combining multiple data sets non-coherently to create a new, single data set. The plurality of data sets may each be obtained from a different steering angle and/or aperture and/or may each be obtained at a different time. The plurality of data sets or steering frames are combined to generate a single view or compound image by combining the data received from each point in the compound image target which has been received from each steering angle or aperture. Real time spatial compound imaging may be performed by acquiring a series of partially overlapping component image frames from substantially independent steering angles. An array transducer may be utilized to implement electronic beam steering and/or electronic translation of the component frames. The component frames are combined into a compound image by summation, averaging, peak detection, or other combinational means. The compounded image may display relatively lower speckle and better specular reflector delineation than a non-spatially compounded ultrasound image from a single angle.
In real time spatial compound imaging, several image acquisitions are needed to produce each new compound image frame. A time difference exists between acquisition of the first steering frame used in constructing the compound image and the last steering frame used in the image. Significant image misregistration may exist due to the time difference between the acquisition of frames. The image misregistration may result in compound image blurring if a large number of steering frames are used to construct the compound image. Relatively less blurring may result if a smaller number of steering frames are used to construct the image. As discussed above, it is generally desirable to acquire a large number of steering frames to maximize the image quality of the compound image. However, a large number of steering frames requires a longer period of time for acquisition, during which blurring may increase to an undesirable level, especially when the array transducer is in motion.